Aortic Valve Stenosis Causes Accumulation of Extracellular Hemoglobin and Systemic Endothelial Dysfunction.

BACKGROUND: Whether aortic valve stenosis (AS) can adversely affect systemic endothelial function independently of standard modifiable cardiovascular risk factors is unknown. METHODS: We therefore investigated endothelial and cardiac function in an experimental model of AS mice devoid of standard modifiable cardiovascular risk factors and human cohorts with AS scheduled for transcatheter aortic valve replacement. Endothelial function was determined by flow-mediated dilation using ultrasound. Extracellular hemoglobin (eHb) concentrations and NO consumption were determined in blood plasma of mice and humans by ELISA and chemiluminescence. This was complemented by measurements of aortic blood flow using 4-dimensional flow acquisition by magnetic resonance imaging and computational fluid dynamics simulations. The effects of plasma and red blood cell (RBC) suspensions on vascular function were determined in transfer experiments in a murine vasorelaxation bioassay system. RESULTS: In mice, the induction of AS caused systemic endothelial dysfunction. In the presence of normal systolic left ventricular function and mild hypertrophy, the increase in the transvalvular gradient was associated with elevated eryptosis, increased eHb and plasma NO consumption; eHb sequestration by haptoglobin restored endothelial function. Because the aortic valve orifice area in patients with AS decreased, postvalvular mechanical stress in the central ascending aorta increased. This was associated with elevated eHb, circulating RBC-derived microvesicles, eryptotic cells, lower haptoglobin levels without clinically relevant anemia, and consecutive endothelial dysfunction. Transfer experiments demonstrated that reduction of eHb by treatment with haptoglobin or elimination of fluid dynamic stress by transcatheter aortic valve replacement restored endothelial function. In patients with AS and subclinical RBC fragmentation, the remaining circulating RBCs before and after transcatheter aortic valve replacement exhibited intact membrane function, deformability, and resistance to osmotic and hypoxic stress. CONCLUSIONS: AS increases postvalvular swirling blood flow in the central ascending aorta, triggering RBC fragmentation with the accumulation of hemoglobin in the plasma. This increases NO consumption in blood, thereby limiting vascular NO bioavailability. Thus, AS itself promotes systemic endothelial dysfunction independent of other established risk factors. Transcatheter aortic valve replacement is capable of limiting NO scavenging and rescuing endothelial function by realigning postvalvular blood flow to near physiological patterns. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05603520. URL: https://www.clinicaltrials.gov; Unique identifier: NCT01805739.

Multiparametric MRI identifies subtle adaptations for demarcation of disease transition in murine aortic valve stenosis.

Aortic valve stenosis (AS) is the most frequent valve disease with relevant prognostic impact. Experimental model systems for AS are scarce and comprehensive imaging techniques to simultaneously quantify function and morphology in disease progression are lacking. Therefore, we refined an acute murine AS model to closely mimic human disease characteristics and developed a high-resolution magnetic resonance imaging (MRI) approach for simultaneous in-depth analysis of valvular, myocardial as well as aortic morphology/pathophysiology to identify early changes in tissue texture and critical transition points in the adaptive process to AS. AS was induced by wire injury of the aortic valve. Four weeks after surgery, cine loops, velocity, and relaxometry maps were acquired at 9.4 T to monitor structural/functional alterations in valve, aorta, and left ventricle (LV). In vivo MRI data were subsequently validated by histology and compared to echocardiography. AS mice exhibited impaired valve opening accompanied by significant valve thickening due to fibrotic remodelling. While control mice showed bell-shaped flow profiles, AS resulted not only in higher peak flow velocities, but also in fragmented turbulent flow patterns associated with enhanced circumferential strain and an increase in wall thickness of the aortic root. AS mice presented with a mild hypertrophy but unaffected global LV function. Cardiac MR relaxometry revealed reduced values for both T1 and T2 in AS reflecting subtle myocardial tissue remodelling with early alterations in mitochondrial function in response to the enhanced afterload. Concomitantly, incipient impairments of coronary flow reserve and myocardial tissue integrity get apparent accompanied by early troponin release. With this, we identified a premature transition point with still compensated cardiac function but beginning textural changes. This will allow interventional studies to explore early disease pathophysiology and novel therapeutic targets.

Doctor Versus Artificial Intelligence: Patient and Physician Evaluation of Large Language Model Responses to Rheumatology Patient Questions in a Cross-Sectional Study.

OBJECTIVE: The objective of the current study was to assess the quality of large language model (LLM) chatbot versus physician-generated responses to patient-generated rheumatology questions. METHODS: We conducted a single-center cross-sectional survey of rheumatology patients (n = 17) in Edmonton, Alberta, Canada. Patients evaluated LLM chatbot versus physician-generated responses for comprehensiveness and readability, with four rheumatologists also evaluating accuracy by using a Likert scale from 1 to 10 (1 being poor, 10 being excellent). RESULTS: Patients rated no significant difference between artificial intelligence (AI) and physician-generated responses in comprehensiveness (mean 7.12 ± SD 0.99 vs 7.52 ± 1.16; P = 0.1962) or readability (7.90 ± 0.90 vs 7.80 ± 0.75; P = 0.5905). Rheumatologists rated AI responses significantly poorer than physician responses on comprehensiveness (AI 5.52 ± 2.13 vs physician 8.76 ± 1.07; P < 0.0001), readability (AI 7.85 ± 0.92 vs physician 8.75 ± 0.57; P = 0.0003), and accuracy (AI 6.48 ± 2.07 vs physician 9.08 ± 0.64; P < 0.0001). The proportion of preference to AI- versus physician-generated responses by patients and physicians was 0.45 ± 0.18 and 0.15 ± 0.08, respectively (P = 0.0106). After learning that one answer for each question was AI generated, patients were able to correctly identify AI-generated answers at a lower proportion compared to physicians (0.49 ± 0.26 vs 0.97 ± 0.04; P = 0.0183). The average word count of AI answers was 69.10 ± 25.35 words, as compared to 98.83 ± 34.58 words for physician-generated responses (P = 0.0008). CONCLUSION: Rheumatology patients rated AI-generated responses to patient questions similarly to physician-generated responses in terms of comprehensiveness, readability, and overall preference. However, rheumatologists rated AI responses significantly poorer than physician-generated responses, suggesting that LLM chatbot responses are inferior to physician responses, a difference that patients may not be aware of.

Hemodynamic management of cardiogenic shock in the intensive care unit.

Hemodynamic derangements are defining features of cardiogenic shock. Randomized clinical trials have examined the efficacy of various therapeutic interventions, from percutaneous coronary intervention to inotropes and mechanical circulatory support (MCS). However, hemodynamic management in cardiogenic shock has not been well-studied. This State-of-the-Art review will provide a framework for hemodynamic management in cardiogenic shock, including a description of the 4 therapeutic phases from initial 'Rescue' to 'Optimization', 'Stabilization' and 'de-Escalation or Exit therapy' (R-O-S-E), phenotyping and phenotype-guided tailoring of pharmacological and MCS support, to achieve hemodynamic and therapeutic goals. Finally, the premises that form the basis for clinical management and the hypotheses for randomized controlled trials will be discussed, with a view to the future direction of cardiogenic shock.

Body Mass Index and Mortality in Cardiogenic Shock.

We explored the association of body mass index (BMI) with mortality in cardiogenic shock (CS). Using the Cardiogenic Shock Working Group registry, we assessed the impact of BMI on mortality using restricted cubic splines in a multivariable logistic regression model adjusting for age, gender, and race. We also assessed mortality, device use, and complications in BMI categories, defined as underweight (<18.5 kg/m2), normal (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), obese (30-39.9 kg/m2), and severely obese (>40 kg/m2) using univariable logistic regression models. Our cohort had 3,492 patients with CS (mean age = 62.1 ± 14 years, 69% male), 58.0% HF-related CS (HF-CS), and 27.8% acute myocardial infarction (AMI) related CS. Body mass index was a significant predictor of mortality in multivariable regression using restricted cubic splines (p < 0.0001, p = 0.194 for nonlinearity). When stratified by categories, patients with healthy weight had lower mortality (29.0%) than obese (35.1%, p = 0.003) or severely obese (36.7%, p = 0.01). In HF-CS cohort, the healthy weight patients had the lowest mortality (21.7%), whereas it was higher in the underweight (37.5%, p = 0.012), obese (29.2%, p = 0.003), and severely obese (29.9%, p = 0.019). There was no difference in mortality among BMI categories in AMI-CS.

Clinical outcomes among cardiogenic shock patients supported with high-capacity Impella axial flow pumps: A report from the Cardiogenic Shock Working Group.

BACKGROUND: The Impella 5.0 and 5.5 pumps (Abiomed, Danvers, MA) are large-bore transvalvular micro-axial assist devices used in cardiogenic shock (CS) for patients requiring high-capacity flow. Despite their increasing use, real-world data regarding indications, rates of utilization and clinical outcomes with this therapy are limited. The objective of our study was to examine clinical profiles and outcomes of patients in a contemporary, real-world CS registry of patients who received an Impella 5.0/5.5 alone or in combination with other temporary mechanical circulatory support (tMCS) devices. METHODS: The CS Working Group (CSWG) Registry includes patients from 34 US hospitals. For this analysis, data from patients who received an Impella 5.0/5.5 between 2020-2023 were analyzed. Use of Impella 5.0/5.5 with or without additional tMCS therapies, duration of support, adverse events and outcomes at hospital discharge were studied. Adverse events including stroke, limb ischemia, bleeding and hemolysis were not standardized by the registry but reported per individual CSWG Primary Investigator discretion. For those who survived, rates of native heart recovery (NHR) or heart replacement therapy (HRT) including heart transplant (HT), or durable ventricular assist device (VAD) were recorded. We also assessed outcomes based on shock etiology (acute myocardial infarction or MI-CS vs. heart failure-related CS or HF-CS). RESULTS: Among 6,205 patients, 754 received an Impella 5.0/5.5 (12.1%), including 210 MI-CS (27.8%) and 484 HF-CS (64.1%) patients. Impella 5.0/5.5 was used as the sole tMCS device in 32% of patients, while 68% of patients received a combination of tMCS devices. Impella cannulation sites were available for 524/754 (69.4%) of patients, with 93.5% axillary configuration. Survival to hospital discharge for those supported with an Impella 5.0/5.5 was 67%, with 20.4% NHR and 45.5% HRT. Compared to HF-CS, patients with MI-CS supported on Impella 5.0/5.5 had higher in-hospital mortality (45.2% vs 26.2%, p < 0.001) and were less likely to receive HRT (22.4% vs 56.6%, p < 0.001. For patients receiving a combination of tMCS during hospitalization, this was associated with higher rates of limb ischemia (9% vs. 3%, p < 0.01), bleeding (52% vs 33%, p < 0.01), and mortality (38% vs 25%; p < 0.001) compared to Impella 5.0/5.5 alone. Among Impella 5.0/5.5 recipients, the median duration of pump support was 12.9 days (IQR: 6.8-22.9) and longer in patients bridged to HRT (14 days; IQR: 7.7-28.4). CONCLUSIONS: In this multi-center cohort of patients with CS, use of Impella 5.0/5.5 was associated with an overall survival of 67.1% and high rates of HRT. Lower adverse event rates were observed when Impella 5.0/5.5 was the sole support device used. Further study is required to determine whether a strategy of early Impella 5.0/5.5 use for CS improves survival. CONDENSED ABSTRACT: High capacity Impella heart pumps are capable of provide up to 5.5 liter/min of flow while upper body surgical placement allows for ambulation. Patients with advanced cardiogenic shock from acute myocardial infarction or heart failure requiring temporary mechanical circulatory support may benefit from upfront use of Impella 5.5 to improve overall survival, including native heart recovery or successful bridge to durable left ventricular assist device surgery or heart transplantation.

Factors associated with Acute Limb Ischemia in Cardiogenic Shock and downstream Clinical Outcomes: Insights from the Cardiogenic Shock Working Group.

BACKGROUND: There are limited data depicting the prevalence and ramifications of acute limb ischemia (ALI) among cardiogenic shock (CS) patients. METHODS: We employed data from the Cardiogenic Shock Working Group (CSWG), a consortium including 33 sites. We constructed a multi-variable logistic regression to examine the association between clinical factors and ALI, we generated another logistic regression model to ascertain the association of ALI with mortality. RESULTS: There were 7,070 patients with CS and 399 (5.6%) developed ALI. Patients with ALI were more likely to be female (40.4% versus 29.4%) and have peripheral arterial disease (13.8% versus 8.3%). Stratified by maximum SCAI shock stage, the rates of ALI were stage B 0.0%, stage C 1.8%, stage D 4.1%, and stage E 10.3%. Factors associated with higher risk for ALI included: peripheral vascular disease OR 2.24 (95% CI: 1.53 - 3.23; p < 0.01) and ≥ 2 mechanical circulatory support (MCS) devices OR 1.66 (95% CI: 1.24 - 2.21, p < 0.01). ALI was highest for VA-ECMO patients (11.6%) or VA-ECMO + IABP/Impella CP (16.6%) yet use of distal perfusion catheters was less than 50%. Mortality was 38.0% for CS patients without ALI but 57.4% for CS patients with ALI. ALI was significantly associated with mortality, adjusted OR 1.40 (95% CI 1.01 - 1.95, p < 0.01). CONCLUSIONS: The rate of ALI was 6% among CS patients. Factors most associated with ALI include peripheral vascular disease and multiple MCS devices. The downstream ramifications of ALI were dire with a considerably higher risk of mortality.

Receptor autoantibodies: Associations with cardiac markers, histology, and function in human non-ischaemic heart failure.

AIMS: A causal link between non-ischaemic heart failure (HF) and humoral autoimmunity against G-protein-coupled receptors (GPCR) remains unclear except for Chagas' cardiomyopathy. Uncertainty arises from ambiguous reports on incidences of GPCR autoantibodies, spurious correlations of autoantibody levels with disease activity, and lack of standardization and validation of measuring procedures for putatively cardio-pathogenic GPCR autoantibodies. Here, we use validated and certified immune assays presenting native receptors as binding targets. We compared candidate GPCR autoantibody species between HF patients and healthy controls and tested associations of serum autoantibody levels with serological, haemodynamic, metabolic, and functional parameters in HF. METHODS: Ninety-five non-ischaemic HF patients undergoing transcatheter endomyocardial biopsy and 60 healthy controls were included. GPCR autoantibodies were determined in serum by IgG binding to native receptors or a cyclic peptide (for ß1AR autoantibodies). In patients, cardiac function, volumes, and myocardial structural properties were assessed by cardiac magnetic resonance imaging; right heart catheterization served for determination of cardiac haemodynamics; endomyocardial biopsies were used for histological assessment of cardiomyopathy and determination of cardiac mitochondrial oxidative function by high-resolution respirometry. RESULTS: Autoantibodies against ß1 adrenergic (ß1 AR) , M5-muscarinic (M5AR), and angiotensin II type 2 receptors (AT2R) were increased in HF (all P < 0.001). Autoantibodies against α1 -adrenergic (α1 AR) and angiotensin II type 1 receptors (AT1R) were decreased in HF (all P < 0.001). Correlation of alterations of GPCR autoantibodies with markers of cardiac or systemic inflammation or cardiac damage, haemodynamics, myocardial histology, or left ventricular inflammation (judged by T2 mapping) were weak, even when corrected for total IgG. ß1 AR autoantibodies were related inversely to markers of left ventricular fibrosis indicated by T1 mapping (r = -0.362, P < 0.05) and global longitudinal strain (r = -0.323, P < 0.05). AT2R autoantibodies were associated with improved myocardial mitochondrial coupling as measured by high-resolution respirometry in myocardial biopsies (r = -0.352, P < 0.05). In insulin-resistant HF patients, AT2R autoantibodies were decreased (r = -.240, P < 0.05), and AT1R autoantibodies were increased (r = 0.212, P < 0.05). CONCLUSIONS: GPCR autoantibodies are markedly altered in HF. However, they are correlated poorly or even inversely to haemodynamic, metabolic, and functional markers of disease severity, myocardial histology, and myocardial mitochondrial efficiency. These observations do not hint towards a specific cardio-pathogenic role of GPCR autoantibodies and suggest that further investigations are required before specific therapies directed at GPCR autoantibodies can be clinically tested in non-ischaemic HF.

Prevalence and prognostic impact of dynamic atrial functional mitral regurgitation assessed by isometric handgrip exercise.

AIMS: In atrial functional mitral regurgitation (aFMR), a considerable proportion of patients displays a discrepancy between symptoms and echocardiographic findings at rest. Exercise testing plays a substantial role in assessing the haemodynamic relevance of mitral regurgitation (MR) and is recommended by current guidelines. Here, we aimed to assess the prevalence, extent, and prognostic impact of exercise-induced changes in patients with aFMR. METHODS AND RESULTS: Patients with at least mild MR who underwent handgrip exercise echocardiography at the University Hospital Duesseldorf between January 2019 and September 2021 were enrolled. Patients were followed-up for one year to assess clinical outcomes. Eighty patients with aFMR were included (median age: 80 (77-83) years; 53.8% female). The median N-terminal pro brain natriuretic petide level was 1756 (1034-3340) ng/l. At rest, half of the patients (53.8%) had mild MR, 20 patients (25.0%) had moderate MR, and 17 patients (21.2%) had severe MR. In approximately every fifth patient (17.5%) with non-severe MR at rest, the MR became severe during exercise. Handgrip exercise led to a re-classification of MR severity in 28 patients (35.0%). At one-year follow-up, adverse events occurred more often in patients with severe MR at rest (76.5%) and exercise-induced dynamic severe MR (66.7%) than in those with non-severe MR (28.6%) (p < 0.001). CONCLUSIONS: Handgrip exercise during echocardiography revealed exercise-induced changes in aFMR in every third patient. These data may have implications for therapeutic decision-making in symptomatic patients with non-severe aFMR at rest.

Clinical Course of Patients in Cardiogenic Shock Stratified by Phenotype.

BACKGROUND: Cardiogenic shock (CS) patients remain at 30% to 60% in-hospital mortality despite therapeutic innovations. Heterogeneity of CS has complicated clinical trial design. Recently, 3 distinct CS phenotypes were identified in the CSWG (Cardiogenic Shock Working Group) registry version 1 (V1) and external cohorts: I, "noncongested;" II, "cardiorenal;" and III, "cardiometabolic" shock. OBJECTIVES: The aim was to confirm the external reproducibility of machine learning-based CS phenotypes and to define their clinical course. METHODS: The authors included 1,890 all-cause CS patients from the CSWG registry version 2. CS phenotypes were identified using the nearest centroids of the initially reported clusters. RESULTS: Phenotypes were retrospectively identified in 796 patients in version 2. In-hospital mortality rates in phenotypes I, II, III were 23%, 41%, 52%, respectively, comparable to the initially reported 21%, 45%, and 55% in V1. Phenotype-related demographic, hemodynamic, and metabolic features resembled those in V1. In addition, 58.8%, 45.7%, and 51.9% of patients in phenotypes I, II, and III received mechanical circulatory support, respectively (P = 0.013). Receiving mechanical circulatory support was associated with increased mortality in cardiorenal (OR: 1.82 [95% CI: 1.16-2.84]; P = 0.008) but not in noncongested or cardiometabolic CS (OR: 1.26 [95% CI: 0.64-2.47]; P = 0.51 and OR: 1.39 [95% CI: 0.86-2.25]; P = 0.18, respectively). Admission phenotypes II and III and admission Society for Cardiovascular Angiography and Interventions stage E were independently associated with increased mortality in multivariable logistic regression compared to noncongested "stage C" CS (P < 0.001). CONCLUSIONS: The findings support the universal applicability of these phenotypes using supervised machine learning. CS phenotypes may inform the design of future clinical trials and enable management algorithms tailored to a specific CS phenotype.

Impact of Female Sex on Cardiogenic Shock Outcomes: A Cardiogenic Shock Working Group Report.

BACKGROUND: Studies reporting cardiogenic shock (CS) outcomes in women are scarce. OBJECTIVES: The authors compared survival at discharge among women vs men with CS complicating acute myocardial infarction (AMI-CS) and heart failure (HF-CS). METHODS: The authors analyzed 5,083 CS patients in the Cardiogenic Shock Working Group. Propensity score matching (PSM) was performed with the use of baseline characteristics. Logistic regression was performed for log odds of survival. RESULTS: Among 5,083 patients, 1,522 were women (30%), whose mean age was 61.8 ± 15.8 years. There were 30% women and 29.1% men with AMI-CS (P = 0.03). More women presented with de novo HF-CS compared with men (26.2% vs 19.3%; P < 0.001). Before PSM, differences in baseline characteristics and sex-specific outcomes were seen in the HF-CS cohort, with worse survival at discharge (69.9% vs 74.4%; P = 0.009) and a higher rate of maximum Society for Cardiac Angiography and Interventions stage E (26% vs 21%; P = 0.04) in women than in men. Women were less likely to receive pulmonary artery catheterization (52.9% vs 54.6%; P < 0.001), heart transplantation (6.5% vs 10.3%; P < 0.001), or left ventricular assist device implantation (7.8% vs 10%; P = 0.01). Regardless of CS etiology, women had more vascular complications (8.8% vs 5.7%; P < 0.001), bleeding (7.1% vs 5.2%; P = 0.01), and limb ischemia (6.8% vs 4.5%; P = 0.001). More vascular complications persisted in women after PSM (10.4% women vs 7.4% men; P = 0.06). CONCLUSIONS: Women with HF-CS had worse outcomes and more vascular complications than men with HF-CS. More studies are needed to identify barriers to advanced therapies, decrease complications, and improve outcomes of women with CS.

Myocardial Injury Promotes Matrix Metalloproteinase-9 Activity in the Renal Cortex in Preclinical Models of Acute Myocardial Infarction.

New mechanistic insight into how the kidney responds to cardiac injury during acute myocardial infarction (AMI) is required. We hypothesized that AMI promotes inflammation and matrix metalloproteinase-9 (MMP9) activity in the kidney and studied the effect of initiating an Impella CP or veno-arterial extracorporeal membrane oxygenation (VA-ECMO) before coronary reperfusion during AMI. Adult male swine were subjected to coronary occlusion and either reperfusion (ischemia-reperfusion; IR) or support with either Impella or VA-ECMO before reperfusion. IR and ECMO increased while Impella reduced levels of MMP-9 in the myocardial infarct zone, circulation, and renal cortex. Compared to IR, Impella reduced myocardial infarct size and urinary KIM-1 levels, but VA-ECMO did not. IR and VA-ECMO increased pro-fibrogenic signaling via transforming growth factor-beta and endoglin in the renal cortex, but Impella did not. These findings identify that AMI increases inflammatory activity in the kidney, which may be attenuated by Impella support.

Predictors of Postprandial Hypoglycemia After Gastric Bypass Surgery: a Retrospective Case-Control Study.

BACKGROUND: Postprandial hypoglycemia after bariatric surgery is an exigent disorder, often impacting the quality of life. Distinguishing clinically relevant hypoglycemic episodes from symptoms of other origin can be challenging. Diagnosis is demanding and often requires an extensive testing such as prolonged glucose tolerance or mixed-meal test. Therefore, we investigated whether baseline parameters of patients after gastric bypass with suspected hypoglycemia can predict the diagnosis. METHODS: We analyzed data from 35 patients after gastric bypass with suspected postprandial hypoglycemia and performed a standardized mixed-meal test. Hypoglycemia was defined by the appearance of typical symptoms, low plasma glucose, and relief of symptoms following glucose administration. Parameters that differed in patients with and without hypoglycemia during MMT were identified and evaluated for predictive precision using receiver operating characteristic (ROC) areas under the curve (AUC). RESULTS: Out of 35 patients, 19 (54%) developed symptomatic hypoglycemia as a result of exaggerated insulin and C-peptide release in response to the mixed-meal. Hypoglycemic patients exhibited lower glycosylated hemoglobin A1c (HbA1c) and higher absolute and relative weight loss from pre-surgery to study date. HbA1c and absolute weight loss alone could achieve acceptable AUCs in ROC analyses (0.76 and 0.72, respectively) but a combined score of absolute weight loss divided by HbA1c (0.78) achieved the best AUC. CONCLUSIONS: HbA1c and weight loss differed in patients with and without symptomatic hypoglycemia during mixed-meal test. These baseline parameters could be used for screening of postprandial hypoglycemia in patients after gastric bypass and may facilitate the selection of patients requiring further evaluation.

Human myocardial mitochondrial oxidative capacity is impaired in mild acute heart transplant rejection.

AIMS: Acute cellular rejection (ACR) following heart transplantation (HTX) is associated with long-term graft loss and increased mortality. Disturbed mitochondrial bioenergetics have been identified as pathophysiological drivers in heart failure, but their role in ACR remains unclear. We aimed to prove functional disturbances of myocardial bioenergetics in human heart transplant recipients with mild ACR by assessing myocardial mitochondrial respiration using high-resolution respirometry, digital image analysis of myocardial inflammatory cell infiltration, and clinical assessment of HTX patients. We hypothesized that (i) mild ACR is associated with impaired myocardial mitochondrial respiration and (ii) myocardial inflammation, systemic oxidative stress, and myocardial oedema relate to impaired mitochondrial respiration and myocardial dysfunction. METHODS AND RESULTS: We classified 35 HTX recipients undergoing endomyocardial biopsy according International Society for Heart and Lung Transplantation criteria to have no (0R) or mild (1R) ACR. Additionally, we quantified immune cell infiltration by immunohistochemistry and digital image analysis. We analysed mitochondrial substrate utilization in myocardial fibres by high-resolution respirometry and performed cardiovascular magnetic resonance (CMR). ACR (1R) was diagnosed in 12 patients (34%), while the remaining 23 patients revealed no signs of ACR (0R). Underlying cardiomyopathies (dilated cardiomyopathy 50% vs. 65%; P = 0.77), comorbidities (type 2 diabetes mellitus: 50% vs. 35%, P = 0.57; chronic kidney disease stage 5: 8% vs. 9%, P > 0.99; arterial hypertension: 59% vs. 30%, P = 0.35), medications (tacrolimus: 100% vs. 91%, P = 0.54; mycophenolate mofetil: 92% vs. 91%, P > 0.99; prednisolone: 92% vs. 96%, P > 0.99) and time post-transplantation (21.5 ± 26.0 months vs. 29.4 ± 26.4 months, P = 0.40) were similar between groups. Mitochondrial respiration was reduced by 40% in ACR (1R) compared with ACR (0R) (77.8 ± 23.0 vs. 128.0 ± 33.0; P < 0.0001). Quantitative assessment of myocardial CD3+ -lymphocyte infiltration identified ACR (1R) with a cut-off of >14 CD3+ -lymphocytes/mm2 (100% sensitivity, 82% specificity; P < 0.0001). Myocardial CD3+ infiltration (r = -0.41, P < 0.05), systemic oxidative stress (thiobarbituric acid reactive substances; r = -0.42, P < 0.01) and myocardial oedema depicted by global CMR derived T2 time (r = -0.62, P < 0.01) correlated with lower oxidative capacity and overt cardiac dysfunction (global longitudinal strain; r = -0.63, P < 0.01). CONCLUSIONS: Mild ACR with inflammatory cell infiltration associates with impaired mitochondrial bioenergetics in cardiomyocytes. Our findings may help to identify novel checkpoints in cardiac immune metabolism as potential therapeutic targets in post-transplant care.

Machine Learning Identifies Clinical Parameters to Predict Mortality in Patients Undergoing Transcatheter Mitral Valve Repair.

OBJECTIVES: The aim of this study was to develop a machine learning (ML)-based risk stratification tool for 1-year mortality in transcatheter mitral valve repair (TMVR) patients incorporating metabolic and hemodynamic parameters. BACKGROUND: The lack of appropriate, well-validated, and specific means to risk-stratify patients with mitral regurgitation complicates the evaluation of prognostic benefits of TMVR in clinical trials and practice. METHODS: A total of 1,009 TMVR patients from 3 university hospitals within the Heart Failure Network Rhineland were included; 1 hospital (n = 317) served as external validation. The primary endpoint was all-cause 1-year mortality. Model performance was assessed using receiver-operating characteristic curve analysis. In the derivation cohort, different ML algorithms were tested using 5-fold cross-validation. The final model, called MITRALITY (transcatheter mitral valve repair mortality prediction system) was tested in the validation cohort with respect to existing clinical scores. RESULTS: Extreme gradient boosting was selected for the MITRALITY score, using only 6 baseline clinical features for prediction (in order of predictive importance): urea, hemoglobin, N-terminal pro-brain natriuretic peptide, mean arterial pressure, body mass index, and creatinine. In the external validation cohort, the MITRALITY score's area under the curve was 0.783 (95% CI: 0.716-0.849), while existing scores yielded areas under the curve of 0.721 (95% CI: 0.63-0.811) and 0.657 (95% CI: 0.536-0.778) at best. CONCLUSIONS: The MITRALITY score is a novel, internally and externally validated ML-based tool for risk stratification of patients prior to TMVR, potentially serving future clinical trials and daily clinical practice.

Impact of Age on Outcomes in Patients With Cardiogenic Shock.

Background: Advanced age is associated with poor outcomes in cardiovascular emergencies. We sought to determine the association of age, use of support devices and shock severity on mortality in cardiogenic shock (CS). Methods: Characteristics and outcomes in CS patients included in the Cardiogenic Shock Work Group (CSWG) registry from 8 US sites between 2016 and 2019 were retrospectively reviewed. Patients were subdivided by age into quintiles and Society for Cardiovascular Angiography & Interventions (SCAI) shock severity. Results: We reviewed 1,412 CS patients with a mean age of 59.9 ± 14.8 years, including 273 patients > 73 years of age. Older patients had significantly higher comorbidity burden including diabetes, hypertension and coronary artery disease. Veno-arterial extracorporeal membrane oxygenation was used in 332 (23%) patients, Impella in 410 (29%) and intra-aortic balloon pump in 770 (54%) patients. Overall in-hospital survival was 69%, which incrementally decreased with advancing age (p < 0.001). Higher age was associated with higher mortality across all SCAI stages (p = 0.003 for SCAI stage C; p < 0.001 for SCAI stage D; p = 0.005 for SCAI stage E), regardless of etiology (p < 0.001). Conclusion: Increasing age is associated with higher in-hospital mortality in CS across all stages of shock severity. Hence, in addition to other comorbidities, increasing age should be prioritized during patient selection for device support in CS.